Disassembly; Tools And Shop Equipment; Accessory Removal; Cleaning - GMC 1989 Light Duty Truck Repair Manual

6A5-6 V8 ENGINE

TOOLS AND SHOP EQUIPMENT

A clean, well lit work area should be available. Other
necessary equipm ent includes: A suitable parts cleaning
tank, compressed air supply, trays to keep parts and
fasteners organized, and an adequate set of hand tools.
An approved engine repair stand will aid the work and
help prevent personal inju ry or dam age to engine
components.
Special tools are illustrated throughout this section, and
are listed at its end. These tools (or their equivalents) are
specially designed to quickly and safely accomplish the
operations for which they are intended. The use of these
tools will also m inim ize possible dam age to engine
components.
Some precision m easuring tools are required for
in s p e c tio n of c e rta in c ritic a l c o m p o n e n ts . Torque
wrenches will be necessary for correct assem bly of
various parts.

ACCESSORY REMOVAL

This manual assumes that the engine accessories have
been removed. These accessories may include one or
more of the following:
Hydraulic Pump
AIR Pump
Generator
Air Conditioning
Compressor
Cooling Fan
It is beyond the scope of this section to detail the many
different accessory installations. Refer to the proper Truck
Service Manual for this information.
Diagrams of emission and vacuum hose routings,
wiring harness routing, accessory drive belt layout, etc.,
should be made before removing accessories.

CLEANING

Remove the engine accessories before cleaning, to
provide better access to engine exterior surfaces. After
removing the carburetor, distributor, fuel pump, etc., cover
the openings with tape to prevent the entry of water,
solvent, and dirt.
Methods used to clean the engine will depend on the
aids which are available. Steam cleaning, pressure
w ashing, or so lve nt clea nin g are som e acceptable
methods. Allow the engine to dry before beginning the
work.
It is important that the engine be as clean as possible to
p re v e n t d ir t fro m e n te rin g c r itic a l a re a s d u rin g

disassembly.

DISASSEMBLY
Distributor
Carburetor
Fuel Pump
EGR Valve and
Emission Control
Equipment

DRAINING THE ENGINE

+ + Rem ove or Disconnect
1. Oil pan drain plug. Allow the oil pan to drain.
2. Oil filter.
3. Block drain plugs. Allow the coolant to drain.
4 4
Install or C onnect
-
1. Oil pan drain plug.
&
T ighten
• Oil pan drain plug to 28 N-m (20 ft. lbs.
2. Block drain plugs.
Tighten
• Block drain plugs to 12.7 N m (112 in. lbs.).

EXHAUST MANIFOLD REMOVAL

□ R em ove or D isconnect (Figures 4 and 5)
1. Oil d ip stick tube.
5.0 L
• On and
manifolds, bend back the tab w ashers
2. Bolts and studs (4).
3. (3)
Tab w ashers and w ashers (2) (som e
L
engines).
4. H eat shields (6) (if used).
5. Exhaust manifold (1). Take care not to damage the
AIR injection tubes (if used).

WATER PUMP REMOVAL

4-4
R em ove or D isconnect (Figure 6)
1. Bolts (12).
2. W ater pum p (10).
3. Gaskets (11).

INTAKE MANIFOLD REMOVAL

4-4
R em ove or D isconnect (Figures 7 and 8)
1. Bolts (20).
2. Intake m anifold (21).
— Pull the intake manifold up.
— Do not attempt to loosen the manifold by
prying under the gasket surface with any
tool.
3. Gaskets (22).
4. Seals (23) (7.4 L engines).
5.7 L
en g in es with cast iron
(3).
5.0 L
and
5.7